1. Field of the Invention
The present invention generally relates to a field of universal serial bus, and more particularly to a universal serial bus controller and a universal serial bus host with a specific pin arrangement which is designed according to USB standards.
2. Description of Prior Art
Universal Serial Bus (hereinafter referred to as “USB”) is an interface which is currently widely used Nowadays, the USB 3.0 standard has been developed. The signal transmission rate of USB 3.0 standard can reach 5 Gbps (Gigabit per second).
Furthermore, USB Implementers Forum (USB-IF) has released a connection interface of USB 3.1 standard. In USB 3.1 standard, a Type-C interface has a signal transmission rate of 10 Gbps. A connector with the Type-C interface can be inserted into a corresponding device in both orientations when the connector with the Type-C interface is utilized.
In general, a USB connecting system comprises a USB device connected to a USB host via a USB cable. The USB host comprises a wiring substrate, a USB connecting port, and a USB controller which are disposed on the wiring substrate. The USB device is connected to the USB connecting port via a USB connector at one end of the USB cable, so as to be electrically connected to the USB controller on the wiring substrate. Since both USB 3.0 standard and USB 3.1 standard have a high signal transmission rate, a high operating frequency is required. However, in the Type-C interface of USB standard released by the USB-IF, a first group of connecting port signal contacts and a second group of connecting port signal contacts are disposed in both the USB connector and the USB connecting port with the Type-C interface, so as to meet the demand that the USB connector can be inserted into the USB connecting port in both orientations by a user. When the USB connector is electrically connected to the USB connecting port, one of the first and second groups of connecting port signal contacts can provide signal transmission. Each of the first and second groups of connecting port signal contacts at least comprises a set of transmitting signal contacts, a set of receiving signal contacts, and a set of differential signal contacts. As shown in FIG. 1, the USB connector 112 with the Type-C interface comprises a flat board 1120 disposed therein. A-side contacts A1-A12 and B-side contacts B1-B12 are respectively disposed at two sides of the flat board 1120. A2, A3, A6, A7, B11, and B10 are the transmitting signal contacts, the differential signal contacts, and the receiving signal contacts of the first group of connecting port signal contacts. A1 and B12 are ground contacts of the first group of connecting port signal contacts. A4 and B9 are power contacts of the first group of connecting port signal contacts. A10, A11, B2, B3, B6, and B7 are the receiving signal contacts, the transmitting signal contacts, and the differential signal contacts of the second group of connecting port signal contacts. B1 and A12 are ground contacts of the second group of connecting port signal contacts. B4 and A9 are power contacts of the second group of connecting port signal contacts.
However, USB 3.0 standard and USB 3.1 standard have reached the high-speed signal transmission rate of 5 Gbps and 10 Gbps. During a high-speed transmission, interferences among signals significantly affect a transmission performance of the above-mentioned system, especially when a handshaking process is implemented between the USB device and the USB controller. The handshaking process might fail due to a misjudgment of a state machine caused by the interferences among the signals. That is, the USB device fails to be electrically connected to the USB controller. Furthermore, in the standard contact definition of the USB connecting port with the Type-C interface, the interferences among the signals easily occurs because the transmitting signal contacts are too close to the USB controller. Consequently, there is a need to solve the problem of the interference among the signals in the transmission path between the USB device and the USB controller.